0000000000939471
AUTHOR
E. Martínez
showing 24 related works from this author
Prediction of cardiovascular disease by the framingham-REGICOR equation in the high-risk PREDIMED cohort: Impact of the mediterranean diet across dif…
2017
Background-The usefulness of cardiovascular disease (CVD) predictive equations in different populations is debatable. We assessed the efficacy of the Framingham-REGICOR scale, validated for the Spanish population, to identify future CVD in participants, who were predefined as being at high-risk in the PREvención con DIeta MEDiterránea (PREDIMED) study-a nutrition-intervention primary prevention trial-and the impact of adherence to the Mediterranean diet on CVD across risk categories. Methods and Results-In a post hoc analysis, we assessed the CVD predictive value of baseline estimated risk in 5966 PREDIMED participants (aged 55-74 years, 57% women; 48% with type 2 diabetes mellitus). Major …
Large scale synthesis of nanostructured zirconia-based compounds from freeze-dried precursors
2013
Nanocrystalline zirconia powders have been obtained at the multigram scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous acetic solutions. This technique has equally made possible to synthesize a variety of nanostructured yttria or scandia doped zirconia compositions. SEM images, as well as the analysis of the XRD patterns, show the nanoparticulated character of those solids obtained at low temperature, with typical particle size in the 10–15 nm range when prepared at 673 K. The presence of the monoclinic, the tetragonal or both phases depends on the temperature of the thermal treatment, the doping concentration and the nature of the dopant. In addition,…
La cueva de El Sidrón (Borines, Piloña, Asturias): primeros resultados
2003
Se exponen los resultados preliminares de las excavaciones arqueológicas llevadas a cabo en la Cueva de El Sidrón entre 2000 y 2002, de acuerdo con los tres objetivos principales que conciernen al registro fósil humano: las características antropológicas, cómo y cuándo llegaron allí y la relación entre fósiles y cultura. Las primeras conclusiones obtenidas son que los restos humanos pertenecen al Neandertal, que el registro arqueológico corresponde a un tecno-complejo del Paleolítico Medio y que están en posición secundaria
Electronic Properties of Mixed-Valence Manganates: The Role of Mn Substitutional Defects
2002
Single-phase perovskites in the solid solution series La0.7+yA0.3-yMn1-xMxO3 (with 0.00 ≤ x ≤ 0.10; A = Sr2+, M = Cu2+, Zn2+, Sc3+, Cr3+, Co3+, and Ga3+; A = Ba2+, M = Cu2+, Zn2+, and Sc3+) have been prepared via the acetic acid solutions freeze-drying method. This soft procedure makes possible strict stoichiometric control, and the synthetic variables allow one to maintain a constant proportion of Mn4+ (ca. 32%) in the 47 compounds prepared. In this way, the concentration of cationic vacancies at A and B sites is practically negligible in all cases. X-ray powder diffraction patterns corresponding to the 47 compounds have been completely indexed with rhombohedral perovskite cells. The cryst…
Caracterización de barita cubana y su reducción carbotérmica en horno de microondas
2007
The Cuban Barite (BaSO4) is characterized by X ray diffraction, chemical analysis and scanning electron microscopy. The principal components are identified and its characteristic morphology is shown. Its carbothermic reduction under microwave irradiation is carried out with the purpose of to improve the yield of this stage during the mineral transformation process in reagent of barium of diverse applications. La barita cubana (BaSO4) se ha caracterizado por difracción de rayos X, análisis químico y microscopía electrónica de barrido. Se han identificado sus componentes mayoritarios y así mismo se muestra su morfología característica. Se ha realizado su reducción carbotérmica en horno de mic…
Effect of disorder produced by cationic vacancies at theBsites on the electronic properties of mixed valence manganites
1999
An alloy series of single-phased polycrystalline ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Na}}_{x}{\mathrm{MnO}}_{3+\mathrm{\ensuremath{\delta}}} (0l~xl~0.15)$ has been synthesized in order to study the effect of disorder on the electronic properties of mixed valence manganites. The synthetic variables allow one to maintain a constant proportion of ${\mathrm{Mn}}^{4+}$ in the samples $({\mathrm{Mn}}^{3+}{/\mathrm{M}\mathrm{n}}^{4+}=2.1\ifmmode\pm\else\textpm\fi{}0.2),$ while the similar size of ${\mathrm{La}}^{3+}$ and ${\mathrm{Na}}^{+}$ ions results in no appreciable change in the tolerance factor of the perovskite structure throughout the series. In this way, the sodium content x contro…
Structural effects of Co and Cr substitution in LaMnO3 + δ
2000
Series of perovskite oxides with the composition LaMn1 − xMxO3 + δ (M = Cr, Co; 0 ≤ x ≤ 1) have been synthesized by thermal treatment of precursors obtained by freeze-drying of acetic acid solutions. The oxides have been characterized by X-ray diffraction, and the Mn4+ content and, thus, the oxygen excess, δ, has been determined by redox back-titration. LaMnO3.14 and LaCrO3 phases have the rhombohedral-LaAlO3 and the orthorhombic-GdFeO3 structures, respectively. The LaMn1 − xCrxO3 + δ phases have the rhombohedral structure for x ≤ 0.3, and the orthorhombic structure for x ≥ 0.5. LaCoO3 has, as LaMnO3.14, the rhombohedral structure. However, the LaMn1 − xCoxO3 + δ phases have orthorhombic st…
Surface properties and catalytic performance for ethane combustion of La1−xKxMnO3+δ perovskites
2001
Abstract The influence of K substitution in LaMnO3 perovskite on the surface properties and catalytic oxidation of ethane has been studied. La1−xKxMnO3+δ perovskites (x=0.05, 0.10, 0.15, 0.20 and 0.25) with BET surface area of 20–26 m2 g−1 have been prepared by the freeze-drying method and characterized by X-ray diffraction patterns (XRD), TPR, TPD and XPS. The XRD analyses showed the presence of a single crystalline phase (x≤0.15) with the linear increase of the lattice parameter corroborating the incorporation of potassium in the perovskite structure. The XPS studies revealed an enrichment of the perovskite surface with potassium accompanied by an increase in the surface Mn4+/Mn3+ ratio. …
From nitrides to carbides: topotactic synthesis of the η-carbides Fe3Mo3C and Co3Mo3C
2004
The molybdenum bimetallic interstitial carbides Fe(3)Mo(3)C and Co(3)Mo(3)C have been synthesized by temperature-programmed reaction (TPR) between the molybdenum bimetallic interstitial nitrides Fe(3)Mo(3)N and Co(3)Mo(3)N and a flowing mixture of CH(4) and H(2) diluted in Ar. These compounds have been characterized by X-ray diffraction, laser Raman spectroscopy, elemental analysis, energy dispersive analysis of X rays, thermal analysis (in air) and scanning electron microscopy (field emission). Their structures have been refined from X-ray powder diffraction data. These carbides crystallize in the cubic system, space group Fd3m[a= 11.11376(6) and 11.0697(3)[Angstrom] for Fe and Co compound…
Nanostructured Alumina from Freeze-Dried Precursors
2010
Nanocrystalline alumina has been obtained on the 100 g scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous solutions of different aluminum-containing products, namely aluminum acetate and aluminum L-lactate. Samples prepared at different temperatures (from 873 to 1573 K in steps of 100 K) were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and surface area measurements. In the acetate case, the transformation sequence involves the formation of θ-Al 2 O 3 as an intermediate phase between γ-Al 2 O 3 and α-Al 2 O 3 , whereas this θ phase is not observed in the lactate case. TEM…
Structural evolution of theCuGaO2delafossite under high pressure
2004
We have performed pseudopotential calculations and x-ray-diffraction and x-ray-absorption measurements on the ${\mathrm{CuGaO}}_{2}$ delafossite under high pressure. We have completely characterized the structural behavior of the low pressure phase. We have found out that the a axis is more compressible than the c axis, and as a consequence the oxygen octahedra defined by the gallium environment tend to become more regular under high pressure. We have determined the internal parameter describing the oxygen position inside the unit cell, and seen that it is nearly constant when pressure is applied. We have observed an irreversible phase transition affecting the copper environment but not the…
A new approach to the synthesis of intermetallic compounds: mild synthesis of submicrometric CoxMy (M = Mo, W; x∶y = 3∶1 and 7∶6) particles by direct…
2002
A simple processing route to cobalt–molybdenum and cobalt–tungsten intermetallics (CoxMy, where M = Mo and W, and x∶y = 3∶1 and 7∶6) has been developed, on the basis of the use of precursors resulting from freeze-drying of aqueous solutions of the appropriate common metal salts. The influence of the preparative variables on the outcomes of this procedure is examined. These compounds are prepared as single phases by thermal reduction of amorphous freeze-dried powders under a hydrogen–argon atmosphere (8% H2), followed by slow cooling of the samples. The materials have been characterised by X-ray powder diffraction, metal analysis, scanning electron microscopy and thermogravimetry under an ox…
Microstructure and mechanical properties of plasma spraying coatings from YSZ feedstocks comprising nano-and submicron-sized particles
2015
Atmospheric plasma spraying (APS) is an attractive technique to obtain nanostructured coatings due to its versatility, simplicity and relatively low cost. However, nanoparticles cannot be fed into the plasma using conventional feeding systems, due to their low mass and poor flowability, and must be adequately reconstituted into sprayable micrometric agglomerates. In this work, nanostructured and submicron/nanostiuctured powders of yttria-stabilised zirconia (YSZ) were deposited using APS, with a view to obtaining high-performance thermal bather coatings (IBC). All powders were reconstituted by spray-drying from different solid loading suspensions, followed by a thermal treatment of the spra…
Vibrational properties of delafossiteCuGaO2at ambient and high pressures
2005
In this paper we investigate the vibrational properties of $\mathrm{Cu}\mathrm{Ga}{\mathrm{O}}_{2}$ delafossite by means of Raman experiments and ab initio calculations. Both investigations have been performed at ambient pressure and also at high pressure. The two Raman-active modes have frequencies ${w}_{{E}_{g}}=368\ifmmode\pm\else\textpm\fi{}1\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ and ${w}_{{A}_{1g}}=729\ifmmode\pm\else\textpm\fi{}1\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$, and pressure coefficients $2.78\ifmmode\pm\else\textpm\fi{}0.03\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}∕\mathrm{GPa}$ $({E}_{g})$ and $4.64\ifmmode\pm\else\text…
Precursor-based synthetic pathways to nanometer NdNiO3−x particles
1993
Abstract The oxygen deficient neodymium nickel perovskite, NdNiO3−x, has been obtained by different low temperature-low oxygen pressure synthetic procedures. Besides a solid-matrix based route, both ordered and disordered chemical-precursors have been used as starting products. X-ray powder diffraction shows that the structure of this defective perovskite is orthorhombic. The study of the grain morphology of the products as resulting from the different synthetic procedures indicates that the main parameter determining the average particle size, which is in the nanometer range, is the maximum temperature achieved in the synthesis. Resistivity and DSC measurements show the existence of a meta…
Caracterización de barita cubana y su reducción carbotérmica en horno de microondas
2007
The Cuban Barite (BaSO<sub>4</sub>) is characterized by X ray diffraction, chemical analysis and scanning electron microscopy. The principal components are identified and its characteristic morphology is shown. Its carbothermic reduction under microwave irradiation is carried out with the purpose of to improve the yield of this stage during the mineral transformation process in reagent of barium of diverse applications.<br><br>La barita cubana (BaSO<sub>4</sub>) se ha caracterizado por difracción de rayos X, análisis químico y microscopía electrónica de barrido. Se han identificado sus componentes mayoritarios y así mismo se muestra su morfología caracter…
Nanostructured Solids from Freeze-Dried Precursors: Multigram Scale Synthesis of TiO2 -Based Powders
2012
Nanocrystalline TiO2 and Ti1−xVxO2 (x = 0.01) powders have been prepared by thermal decomposition, in air, of amorphous precursors resulting from the freeze-drying of appropriate solutions. In addition, TiO2−xNy (anatase and rutile) and TiOxNy (rock-salt) have been prepared by thermal treatment in ammonia of a crystalline precursor (TiO2 obtained at 673 K). TEM and SEM images, as well as the analysis of the X-ray diffraction (XRD) patterns, show the nanoparticulated character of those solids obtained at low temperatures, with typical particle sizes in the 10–20 nm range when prepared at 673 K. The UV–Vis results indicate both the insertion of V in the anatase lattice and the feasibility of …
Type of chromosome abnormality affects embryo morphology dynamics.
2016
Objective To study the differences in the cleavage time between types of embryo chromosomal abnormalities and elaborate algorithm to exclude aneuploid embryos according to the likelihood to be euploid. Design Retrospective cohort study. Setting University affiliated private center. Patient(s) Preimplantational genetic screening patients (n = 112) including cases of advanced maternal age, repeated implantation failure, and recurrent miscarriage. A total of 485 embryos were analyzed. Intervention(s) None. Main Outcome Measure(s) All biopsied embryos were cultured in an incubator with time-lapse technology, cleavage timing from insemination to day 3 and all kinetic parameters that have been de…
Synthesis and processing of nanocrystalline tungsten carbide: Towards cemented carbides with optimal mechanical properties
2011
Abstract Nanocrystalline tungsten carbide has been obtained by reduction/carburization at low temperature from precursors obtained by freeze-drying of aqueous solutions. Nanocrystalline WC powders with a adequate content of carbon were mixed with submicrometric Cobalt powder (12 wt.%), obtained by same synthesis method, and sintered in vacuum furnace. The cemented carbides fabricated from experimental powders were compared with both commercial ultrafine and nanocrystalline WC-12Co mixtures consolidated by the same route. The synthesised powders were characterized by X-ray powder diffraction, elemental analysis and scanning and high resolution transmission electron microscopy. On the other h…
Monitoring the carburization of molybdenum bimetallic nitrides and oxynitrides with CH4/H2/Ar mixtures: identification of a new carbonitride.
2008
A new carbonitride Ni2Mo3(CxNy) has been synthesized by temperature-programmed carburization of the Ni2Mo3N precursor with a CH4/H2/Ar gas mixture at 923 K. This compound has been characterized by X-ray diffraction, elemental analysis, Auger electron spectroscopy, laser Raman spectroscopy, thermogravimetric analysis and field-emission scanning electron microscopy. Ni2Mo3(CxNy) crystallizes in the cubic space group P4(1)32, with a lattice parameter of a=6.64575(3) A, corresponding to the unusual filled beta-Mn structure. Its formation occurs by partial substitution of N by C via a topotactic and pseudomorphic reaction and its stability in air is higher that of Ni2Mo3N. A two-phase mixture wi…
La Cueva de El Sidrón (Piloña Asturias)
2014
Estado de las excavaciones y estudios en la Cueva de El Sidrón (PIloña, Asturias).
Potato consumption does not increase blood pressure or incident hypertension in 2 cohorts of Spanish adults
2017
5 Tablas
Dietary α-Linolenic Acid, Marine ω-3 Fatty Acids, and Mortality in a Population With High Fish Consumption: Findings From the PREvención con DIeta ME…
2016
12 Páginas.-- 6 Tablas.-- 1 Figura
Intraoperative transfusion practices in Europe
2016
PubMed: 26787795